THERMOCHEMICAL PRODUCTION OF HYDROGEN BY METHANE-METHANOL-IODOMETHANE CYCLE

摘要

A thermochemical production method of hydrogen by a methane-methanol-iodomethane cycle is provided to produce hydrogen at low cost and high efficiency by maintaining a standard Gibbs free energy value of an iodomethane reaction step of methanol in an existing methane-methanol-iodomethane cycle as a negative value, thereby inducing a spontaneous reaction. In a thermochemical production method of hydrogen by a methane-methanol-iodomethane cycle comprising: a steam reforming reaction step of a hydrocarbon gas such as methane; a step of converting carbon monoxide produced from the steam reforming reaction into methanol; a step of subjecting the produced methanol to iodination to obtain iodomethane; and a step of hydrolyzing the produced iodomethane, the thermochemical production method of hydrogen is characterized in that the step of subjecting the methanol to iodination comprises the steps of: (a) reacting methanol and sulfur dioxide with iodine recovered from the hydrolysis of the iodomethane to produce iodomethane and sulfuric acid; (b) decomposing the produced sulfuric acid into sulfur trioxide and water; (c) decomposing the produced sulfur trioxide into sulfur dioxide and oxygen in the presence of a composite catalyst of titania and zirconia; (d) circulating the produced sulfur dioxide to the step(a) to reuse the sulfur dioxide; and (e) circulating water produced in the step(b) to the step of hydrolyzing the iodomethane to reuse the water, wherein a standard Gibbs free energy of the iodomethane reaction step of the methane is maintained as a negative value by decomposition and recombination reactions of sulfuric acid.